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United States Patent | 5,636,309 |
Henry ,   et al. | June 3, 1997 |
The disclosed Mach-Zehnder (MZ)-type devices are planar waveguide devices, with interferometer arms of essentially equal length, with a maximum spacing between the arms (e.g., between the waveguide core centers) selected to make possible simultaneous exposure of both arms to refractive index-altering radiation. Exemplarily the maximum spacing is in the range 20-100 .mu.m. The simultaneous exposure of both waveguides makes it possible to form gratings of essential equal strength, such that typically no individual trimming is required. The resulting devices (typically add-drop filters) are substantially less sensitive to environmental changes (e.g., temperature gradients, mechanical vibrations) than prior art fiber-based devices, and are advantageously used in, for instance, WDM optical communication systems.
Inventors: | Henry; Charles H. (Skillman, NJ); Kohnke; Glenn E. (Chatham, NJ); Strasser; Thomas A. (Chatham, NJ) |
Assignee: | Lucent Technologies Inc. (Murray Hill, NJ) |
Appl. No.: | 604629 |
Filed: | February 21, 1996 |
Current U.S. Class: | 385/129 |
Intern'l Class: | G02B 006/10 |
Field of Search: | 385/27,9,31,39,129-132,147 |
4900119 | Feb., 1990 | Hill et al. | 385/31. |
5195161 | Mar., 1993 | Adar et al. | 385/129. |
5276743 | Jan., 1994 | Penner et al. | 385/145. |
5459801 | Oct., 1995 | Snitzer | 385/30. |
"An All-Fiber Dense-Wavelength-Division Multiplexer/Demultiplexer Using Photoimprinted Bragg Gratings", by F. Bilodeau et al., IEEE Photonics Technology Letters, vol. 7, No. 4, Apr. 1995, pp. 388-390. "Laser-Trimmed Four-Port Bandpass Filter Fabricated in Single-Mode Photosensitive Ge-Doped Planar Waveguide", by R. Kashyap et al., IEEE Photonics Technology Letters, vol. 5, No. 2, Feb. 1993, pp. 191-194. "Four-Channel Wavelength Division Multiplexers and Bandpass Filters Based on Elliptical Bragg Reflectors", by C. H. Henry et al., Journal of Lightwave Technology, vol. 8, No. 5, May 1990, pp. 748-755. "Glass Waveguides on Silicon for Hybrid Optical Packaging", by C. H. Henry, Journal of Lightwave Technology, vol. 7, No. 10, Oct. 1989, pp. 1530-1539. |